/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.rolling;

import static ch.qos.logback.core.CoreConstants.CODES_URL;

import java.io.File;
import java.time.Instant;
import java.time.ZoneId;
import java.util.Locale;
import java.util.TimeZone;
import java.util.concurrent.atomic.AtomicLong;

import ch.qos.logback.core.CoreConstants;
import ch.qos.logback.core.rolling.helper.ArchiveRemover;
import ch.qos.logback.core.rolling.helper.DateTokenConverter;
import ch.qos.logback.core.rolling.helper.RollingCalendar;
import ch.qos.logback.core.spi.ContextAwareBase;

/**
 * Base implementation of {@link TimeBasedFileNamingAndTriggeringPolicy}.
 *
 * <p>See also derived classes {@link DefaultTimeBasedFileNamingAndTriggeringPolicy} and
 * {@link SizeAndTimeBasedFileNamingAndTriggeringPolicy}.
 *
 * </p>
 *
 * @param <E>
 */
abstract public class TimeBasedFileNamingAndTriggeringPolicyBase<E> extends ContextAwareBase
        implements TimeBasedFileNamingAndTriggeringPolicy<E> {

    static private String COLLIDING_DATE_FORMAT_URL = CODES_URL + "#rfa_collision_in_dateFormat";

    protected TimeBasedRollingPolicy<E> tbrp;

    protected ArchiveRemover archiveRemover = null;
    protected String elapsedPeriodsFileName;
    protected RollingCalendar rc;

    protected long artificialCurrentTime = -1;

    protected AtomicLong atomicNextCheck = new AtomicLong(0);
    protected Instant dateInCurrentPeriod = null;

    protected boolean started = false;
    protected boolean errorFree = true;

    protected ZoneId zoneId = ZoneId.systemDefault();

    public boolean isStarted() {
        return started;
    }

    public void start() {
        DateTokenConverter<Object> dtc = tbrp.fileNamePattern.getPrimaryDateTokenConverter();
        if (dtc == null) {
            throw new IllegalStateException(
                    "FileNamePattern [" + tbrp.fileNamePattern.getPattern() + "] does not contain a valid DateToken");
        }

        if (dtc.getZoneId() != null) {
            this.zoneId = dtc.getZoneId();
            TimeZone tz = TimeZone.getTimeZone(zoneId);
            rc = new RollingCalendar(dtc.getDatePattern(), tz, Locale.getDefault());
        } else {
            rc = new RollingCalendar(dtc.getDatePattern());
        }
        addInfo("The date pattern is '" + dtc.getDatePattern() + "' from file name pattern '"
                + tbrp.fileNamePattern.getPattern() + "'.");
        rc.printPeriodicity(this);

        if (!rc.isCollisionFree()) {
            addError(
                    "The date format in FileNamePattern will result in collisions in the names of archived log files.");
            addError(CoreConstants.MORE_INFO_PREFIX + COLLIDING_DATE_FORMAT_URL);
            withErrors();
            return;
        }

        long timestamp = getCurrentTime();
        setDateInCurrentPeriod(timestamp);

        if (tbrp.getParentsRawFileProperty() != null) {
            File currentFile = new File(tbrp.getParentsRawFileProperty());
            if (currentFile.canRead()) {
                timestamp = currentFile.lastModified();
                setDateInCurrentPeriod(timestamp);
            }
        }
        addInfo("Setting initial period to " + dateInCurrentPeriod);
        long nextCheck = computeNextCheck(timestamp);
        atomicNextCheck.set(nextCheck);
    }

    public void stop() {
        started = false;
    }

    protected long computeNextCheck(long timestamp) {
        return rc.getNextTriggeringDate(Instant.ofEpochMilli(timestamp)).toEpochMilli();
    }

    public String getElapsedPeriodsFileName() {
        return elapsedPeriodsFileName;
    }

    public String getCurrentPeriodsFileNameWithoutCompressionSuffix() {
        return tbrp.fileNamePatternWithoutCompSuffix.convert(dateInCurrentPeriod);
    }

    protected void setDateInCurrentPeriod(long timestamp) {
        dateInCurrentPeriod = Instant.ofEpochMilli(timestamp);
    }

    public void setCurrentTime(long timeInMillis) {
        artificialCurrentTime = timeInMillis;
    }

    public long getCurrentTime() {
        // if time is forced return the time set by user
        if (artificialCurrentTime >= 0) {
            return artificialCurrentTime;
        } else {
            return System.currentTimeMillis();
        }
    }

    public void setTimeBasedRollingPolicy(TimeBasedRollingPolicy<E> _tbrp) {
        this.tbrp = _tbrp;

    }

    public ArchiveRemover getArchiveRemover() {
        return archiveRemover;
    }

    protected void withErrors() {
        errorFree = false;
    }

    protected boolean isErrorFree() {
        return errorFree;
    }

}
